Refrigeration systems typically include a compressor, an evaporator, an expansion valve, a condenser, and a fan which operate together to cool a refrigerated space. The compressor, expansion valve, condenser, and evaporator are fluidly coupled such that a loop or a closed system exists for circulation of a refrigerant therein. The compressor receives the refrigerant in a gaseous form from the evaporator and pressurizes the gas such that the gas can be changed from the gaseous state into a liquid state in the condenser. Once the refrigerant reaches the liquid state in the condenser, the refrigerant is sent through an expansion valve before reaching the evaporator, which is held at a low pressure by the operation of the expansion valve and the compressor. The low pressure of the evaporator causes the refrigerant to change state back to a gas, and as it does so, absorb heat from an air stream moving through the evaporator. In this manner, the air stream flowing through the evaporator is cooled and the temperature of the refrigerated space is lowered.
The fan is typically disposed proximate the evaporator and is operable to generate a flow of air through the evaporator and into a refrigerated space. As previously discussed, an air flow through the evaporator is cooled as a liquid refrigerant passes therethrough. In this regard, the air flow may be regulated to control the temperature of the exiting air stream and the overall temperature of the refrigerated space.
In conventional refrigeration systems, such as those used in HVAC systems, a bank of condenser units are commonly used in conjunction with a bank of evaporators to cool a plurality of refrigerated spaces. In such a situation, each condenser unit includes a compressor fluidly coupled to the bank of evaporator units, whereby the evaporator units are disposed within a building generally proximate a refrigerated space and the condenser units are disposed outside of the building and are operable to expel heat absorbed by the evaporator units. Having the plurality of condenser units in fluid communication with the evaporator units provides the refrigeration system with flexibility as each condenser unit and accompanying compressor unit may be independently activated to provide a desired amount of liquid refrigerant to each of the evaporator units, thereby evenly controlling the cooling of each refrigerated space.
In such a refrigeration system, an oil distribution system is commonly used to control the oil flow between each compressor to properly lubricate the internal components of each compressor. The oil distribution system commonly includes a plurality of oil conduits fluidly coupling each compressor unit to a central oil reservoir to ensure that sufficient lubrication oil is maintained at each of the compressor locations. In this manner, an oil separation device is provided upstream of each condenser unit to inhibit movement of lubrication oil from the compressors to the evaporators via exiting refrigerant. Specifically, the oil separation device prevents any oil spilled over from the individual compressors from entering the refrigeration system and reaching the evaporators. As can be appreciated, any lubrication oil in the refrigeration system generally reduces the effectiveness of the refrigerant, thereby reducing the overall efficiency of the refrigeration system.
While conventional systems adequately supply each of the condensers and associated compressors with a required amount of oil, and adequately separate any lubrication oil from the refrigerant, conventional refrigeration systems suffer from the disadvantage of requiring a complex oil conduit system between each compressor and the centralized oil reservoir.
Therefore, a refrigeration system that effectively separates compressor oil from the refrigerant, while concurrently maintaining the requisite lubrication oil levels within each compressor unit is desirable in the industry. In addition, a refrigeration system that effectively maintains required lubrication oil levels within each compressor without requiring an extensive oil piping arrangement is also desirable. Combining a compressor, oil separator and condenser in a unitary condensing unit having an electronic control system allows use of multiple condensing units in a compact refrigeration system, reduces costly building provisions, allows more indoor space due to equipment reduction, and shortens installation time.